The development of an inexpensive, portable, stable, sensitive and selective biosensor for detection of odorants is a daunting task. Here, we hypothesized the development of a detector layer composed of the protein groups; the olfactory receptors (ORs) and the odorant binding proteins (OBPs), known to bind odorants in animal sensing. We report the design of 13 OR gene-vector constructs, and their subsequent transformation into

Escherichia (E.) coli (BL21 (DE3)-STAR-pLysS) strain. Moreover, we report the expression of several ORs into an in vitro wheat germ extract using three separate detergent mixes for protein solubilization.

In addition, we describe the design of an odorant binding protein from the Aenopheles gambiae mosquito PEST strain (OBP-PEST) gene-vector construct under an IPTG (Isopropyl β-D-1-thiogalactopyranoside)inducible promoter. OBP-PEST was heterologously expressed in E.coli with an 8 amino acid long sequence (WSPQFEK) attached C-terminally, via a thrombin cleavage site and a ﬂexible linker (GSSG). The WSPQFEK sequence, commonly referred to as a Strep-tag, enabled subsequent afﬁnity chromatography puriﬁcation of the protein, via binding to an engineered Streptavidin equivalent. Surprisingly, the OBP-PEST was found to contain a signal sequence leading to its truncation and secretion when expressed in E.coli.

Biophysical analyses were established using Circular Dichroism (CD) for the analysis of two lipocalins: Beta-lactoglobulin (BLG) and OBP-PEST. We studied the solubility, refoldability and the conformational transitions of BLG, as a result of change in solvent, pH and temperature. The secondary structure of OBP-PEST and its thermal stability was investigated.

In conclusion, this thesis work has enabled biophysical analyses of OBP-PEST and future analogs of interest to the development of a stable protein detector layer. Although further experiments are needed to fully characterize the biophysical properties, and to ﬁnd odorant substrates of OBP-PEST, it was found to be a suitable alternative to ORs in a biosensor detector layer application. More importantly, an inherent OBP-PEST signal sequence was found to mediate protein secretion when expressed heterologously in E.coli. To the best of our knowledge this is the ﬁrst lipocalin discovered to be secreted upon heterologous expression in E.coli.

We hypothesize that this signal peptide could be used as a means for targeted secretion and, hence, efﬁcient protein puriﬁcation.

A cobalt-catalysed, ortho-directed, C-H activation of 8-aminoquinoline amides for the preparation of functionalised isoquinolones is reported. The C-H activation was performed with the amide derived from 8-aminoquinoline which acts as a bidentate directing group to facilitate the C-H activation at the ortho carbon atom of the amide towards annulation/cyclisation, with unsymmetrical 1,3-diynes. The work presented here is an exploration of the regiochemical outcome of an efficient and a novel route of synthesis that tries to gain a deeper insight into the regioselective preference for C-H activated annulations that result in the formation of a diverse range of alkynylated regioisomeric heterocycles. Of the four possible regioisomers, only one is formed as the major product depending on the stereoelectronic properties of the diyne in combination with the nature of the 8-aminoquinoline amide.

Interactions between carbohydrates and proteins play a key role in many biological processes. Cell-cell interactions, cell communication and cell proliferation are examples of processes based on highly specific interactions between proteins and complex oligosaccharides. The synthesis of carbohydrate mimics is essential for the study and understanding of such recognition processes, and has therefore become increasingly popular over the latest decades. In synthesis, thiol derivatives have several advantages. Thus, the combined nucleophilicity and chemical stability of sulfhydryl groups render thiol carbohydrate analogs as excellent building blocks for glycosylation processes. The objectives of the present project were to investigate the differences between naturally occurring oligosaccharides and their sulfur-analogs in biomolecular interactions with specific proteins. Convenient methodologies to the synthesis of a range of D-mannopyranose thioanalogs were developed. These strategies allows for the access to 1,2- and 1,6-linked dimannosides by glycosylation. A carbohydrate-protein interaction methodology to test the developed compounds against a mannose-specific lectin (Concanavalin A) using quartz crystal microbalance (QCM) methodology was furthermore developed.

Electric breakdown in power transformers is preceded by pre-breakdown events such as streamers. The understanding of these phenomena is important in order to optimize liquid insulation systems. Earlier works have derived a model that describes streamers in transformer oil and utilized a finite element method to produce numerical solutions. This research investigates the consequences of changing the numerical method to a finite volume-based solver implemented in OpenFOAM. Using a standardized needle-sphere geometry, a number of oil and voltage combinations were simulated, and the results are for the most part similar to those produced by the previous method. In cases with differing results the change is attributed to the more stable numerical performance of the OpenFOAM solver. A proof of concept for the extension of the simulation from a two-dimensional axial symmetry to three dimensions is also presented.

The potential antimalarial and anticancer effect of molecules containing 1,10-phenanthroline skeleton has been suspected on several previous studies. It is why the goal of this project is to synthesize novel 1,10-phenanthrolines and cyclic analogs.

The originality of this project is the synthesis way of these novel compounds. Indeed, these structures will be obtained through an original redox approach developed in the SMITH laboratory using the tetrakis(dimethylamino)ethylene (TDAE) reagent.

The TDAE is an electron rich organic molecule which is an effective reducing agent capable of generating an anion from halogenated derivatives under mild conditions via a single electron transfer (SET). From the different substrate we will work with, the TDAE will generate an anion which will be additioned on the 1,10-phenanthroline-5,6-dione.

These different substrates will be aromatic and heterocyclic nitro-benzylic, and quinonic derivates as well as bromodifluoromethyl heteroarylated substrates.

A one pot two step (reduction, dehydration) reaction will be done on these addition products, in order to obtain a cyclised product.

It is the first time we try these reactions on these kind on molecules, it is why this project needs a lot of optimization and that the yield obtained are medium or equal to zero. However, we observed that the addition reaction with TDAE worked with 4 substrates out of 6.

We tried the cyclisation reaction on only one addition product and we think that after some improvement of the reaction conditions and the work-up, we will be able to obtain the product with a good yield.

Synthetic glycopeptides have attracted much interest in the biomedical field due to their structural similarities to the natural glycopeptides or glycoproteins. It is still difficult to synthesize glycopeptides with greater efficiency and ring opening polymerization remains an effective way to do so. Proteoglycans are a special class of glycoproteins with glycosaminoglycan chains. In this study, I tried to do controlled ring opening polymerization of Hyaluronic acid derivatives with smaller to higher molecular weight while avoiding side reactions. It is challenging to work with higher molecular weight molecules and do a click reaction in water effectively. Making nanopolymers with a desired size, studies of the characteristics, and how to build nanocarriers for drug delivery application was the focus of this work. Polymeric characteristics, e.g., modification and polymer formation were studied by nuclear magnetic resonance technique; Particle size was studied by dynamic light scattering and the loading of rhodamine B encapsulated into the polymer was measured by confocal imaging technique.

A minor enantiomer recycling one-pot process usingω-functionalized prochiral aldehydes as starting materials and two reinforcing catalysts has been reported. The desired aldehyde for these process studies was 5-bromo-1-pentanal.

In a two-phase solvent system, enzyme-catalyzed hydrolysis of the minor enantiomer regenerates continuously the prochiral starting material and Lewis acid catalysed addition of acetyl cyanide provides the O-acetylated cyanohydrins. The minor enantiomer recycling process has been studied and improved for 5-bromo-1-pentanal to receive high enantiomeric excess and yield of the expected O-acetylated cyanohydrin.

Dye sensitized solar cells are a new type of solar cells which open a new market thanks to their unique properties, which are semi transparency and the fact that they can be produced in various colors.

After improving two existing syntheses for industrial applications, this thesis takes the approach to develop new redox mediators for devices with an aim on improving stability. Five redox mediators with cobalt, copper and iron as metal center were synthesized and characterized by NMR spectroscopy, cyclic voltammetry and UV/VIS spectrophotometry. Three of them were selected for evaluation in test cells. Most promising results were obtained with a copper complex, using the tandem redox approach a new record efficiency of 7.7% for copper based electrolytes in dye-sensitized solar cells was obtained.

10.

Krishna Prasad, Golla

Umeå University, Faculty of Science and Technology, Department of Chemistry.

Multi ring-fused 2-pyridones have shown interesting activity in a variety of biological systems. It would be of great interest to explore the biological application of even more multi heterocyclic ring fused 2-pyridones. ‘Diversity oriented synthesis’ is an excellent concept emerged in recent years to access compounds with structurally and stereochemically diverse skeletons. This served as an efficient avenue for synthesizing various ring fused 2-pyridones using formyl, chloromethylene substituted 2-pyridone (

6) as a starting compound. By treating the starting material (6) with various nucleopliles, different sized heterocyclic ring fused 2-pyridones has been synthesized. Additionally, an improved methodology for the synthesis of naphthyridones was presented.

Today there are strict demands regarding emissions to water and air from the Swedish industries. This degree project, conducted at Smurfit Kappa Piteå, will focus on the emissions of organic material in waste water from the paper mill. The overall goal was through dynamic simulations predict the Total Organic Carbon (TOC) emissions from the paper mill at the time a foreseen increase of production is implemented. The recovery boiler is currently a bottleneck in the process and the production of sulphate pulp has today its maximum capacity. This means that production growth will occur exclusively by increasing the intake of recycled fiber. The work started with a comprehensive mapping of TOC, in which ingoing pulps in pulp towers, head boxes and effluent flows were mapped. This was done over a period of two weeks and thus covered a whole production cycle. A TOC method evaluation was conducted where the most suitable analysis method was determined.

Mapped data were thereupon evaluated and significant variables were identified. It was determined that use of recycled fiber was the single most important variable to TOC load from paper machine 1 (PM1), but also starch addition to paper machine 2 (PM2) was found to be significant.

The work then continued with the simulation phase, consisting of two main parts. The first part consisted of preparatory work where the model was developed to be able to accurately measure TOC load to the waste water treatment plant. This part also included work to identify necessary process changes as a result of an increased production. The second part consisted of the simulation. Three different scenarios were simulated for each paper machine plus two scenarios for the recycled fiber plant. The dynamic simulation model was successively calibrated with respect to TOC concentration and trends followed the ones expected by experience. In the production increase scenario simulated, TOC load distribution between PM1, PM2 and recycled fiber plant will more evenly distributed compared to current production. The largest increase of TOC load will come from the recycled fiber plant, which according to the simulation will increase with about 30 %.

Two series of new mononuclear ruthenium complexes with hydrophobic or hydrophilic ligands [Ru(bda)L2] and [Ru(pdc)L3] (H2bda = 2,2'-bipyridine-6,6'-dicarboxylic acid; H2pdc = 2,6-pyridinedicarboxylic acid; L = pyridyl ligands) were synthesized and their electrochemical properties and catalytic activity toward water oxidation were examined. It was revealed that the hydrophobic ligands introduced to [Ru(bda)L2 ] improved the catalytic performance, ahnost twofold TON and TOF values were achieved compared to the [Ru(bda)] catalyst with hydrophilic ligands. The cyclic voltammogram of [Ru(bda)L2] exhibited marginal difference between the catalysts with hydrophobic ligands and hydrophilic ones, implying that the hydrophobic ligands promoted the catalytic activity by :lacilitating formation of a reaction intermediate dimer.

Immobilization of different bio- and organic molecules on solid supports is fundamental within many areas of science. Sometimes, it is desirable to obtain a directed orientation of the molecule in the immobilized state. In this thesis, the copper (I) catalyzed Huisgen 1,3-dipolar cycloaddition, referred to as a “click chemistry” reaction, was explored as a means to perform directed immobilization of small molecule ligands on gold surfaces. The aim was to synthesize alkyne- and azide-terminated alkanethiols that would form well-organized self assembled monolayers (SAMs) on gold from the commercially available substances orthoethylene glycol and bromo alkanoic acid. N-(23-azido-3,6,9,12,15,18,21-heptaoxatricosyl)-n-mercaptododekanamide/hexadecaneamide (n = 12, 16) were successfully synthesized and allowed to form SAMs of different compositions to study how the differences in density of the functional groups on the surface would influence the structure of the monolayer and the click chemistry reaction. The surfaces were characterized by different optical methods: ellipsometry, contact angle goniometry and infrared reflection-absorption spectroscopy (IRAS). The click reaction was found to proceed at very high yields on all investigated surfaces. Finally, the biomolecular interaction between a ligand immobilized by click chemistry on the gold surfaces and a model protein (bovine carbonic anhydrase) was demonstrated by surface plasmon resonance using a Biacore system.

The aim of the project was to synthesize α1,2-linked and α1,6-linked dimannosides linked through either an oxygen-atom or a sulphur-atom, and subsequently test the binding properties of the dimannosides to lectins with known specificity towards mannose-containing glycans. Thedimannosides were prepared by a glycosylation reaction using selectively protected monosaccharides containing a thiol or alcohol nucleophilic glycosyl acceptor and a series of different glycosyl donors. The synthetic routes to the different building blocks were designed to efficiently make use of common intermediate compounds to streamline the synthesis. The glycosyl acceptors used forthe synthesis of α1,2-linked as well as α1,6-linked dimannosides were synthesized in few steps and diversified only in the last steps of the synthesis. The glycosyl donors used in the study were synthesized from commercially available starting material in a straightforward and convenientsynthesis in 7 to 8 steps.

The purpose of this work has been to investigate the ability of aromatic thiourea and squaramide compounds to catalyze the reversible imine exchange reaction via hydrogen bonding catalysis. The primary goal was to find an organocatalyst that could replace or complement the currently used catalysts, to enable new applications. Parameters such as the catalyst structure and loading, solvent dependence and water content have been explored. The results show that a low pKa of the hydrogen bond-donating hydrogens and a non-coordinating and polar solvent are very important to obtain a short equilibration time. Furthermore, the catalysts are proved to have great activity even at low loadings and to catalyze more than one step in the exchange reaction. The equilibrium time was determined by measuring the integrals of the 1H NMR signals from the imines as the reaction proceeded.

The task of medicinal chemists in a drug discoveryproject is to synthesize/design analogues to the screening hits, simultaneouslyincreasing target potency and optimizing the pharmacological properties. This requires a wide selection of moleculesto be synthesized, where both synthetic feasibility and price of startingmaterials are of great importance. In this work, a synthetic pathway from cheapand readily available starting materials to highly modifiable 2,4-disubstitutedpyrrolidines is demonstrated. Previously reported procedures to similarpyrrolidines use expensive catalysts, requires harsh conditions and requiresnon-commercially available starting materials. The suggested pathway herein has demonstrated great possibility forvariation in the 4-position, including fluoro, difluoro, nitrile and alcoholfunctional groups. There are several areas in which the synthesis can beimproved and expanded upon. Improvements can be made by optimizing thedescribed reaction conditions and further expansion of possible modificationsin both 2- and 4-position could be explored.

This report describes the synthesis of thiomonosaccharides and the subsequent oxidation to carbohydrate disulfides followed by evaluation of a desulfurization reaction with the aim of developing a facile method for production of S-linked oligosaccharides. The carbohydrate disulfides were synthesized in few steps from commercially available starting materials. Small and simple disulfides were used to evaluate the desulfurization process yielding important information about choice of solvent, catalyst and temperature required for the desulfurization to occur. The optimized conditions were then applied to the carbohydrate disulfides. Results showed that the reactivity of the carbohydrate disulfides depends a lot on the position of the disulfide. One of the carbohydrate disulfides was efficiently desulfurized giving the thioether linked disaccharide, as determined by mass spectrometry. However, more work is needed to develop a general procedure for the desulfurization working on many different carbohydrate disulfides.

The need of efficient and sustainable chemical processes in the field of organic chemistry is essential in order to meet the environmental demands that societies and industries require from us. One key chemical reaction that is widely used in industrial plants is olefin metathesis, a reaction that involves exchange and formation of C-C double bonds. It is a crucial reaction in polymerization reactions and as a means of connecting building blocks together. Consequently it is necessary to enable these reactions to work in aqueous media for increased sustainability and for applications in biochemistry. Carbenes are a class of compounds that constitute a crucial role as ligands in olefin metathesis catalysts. This project will aim to explore the water applicability of a certain category of carbenes, cyclic (alkyl)-(amino)carbenes (CAAC), which recently have caught attention due to their remarkable catalytic activity in organometallic catalysis. The CAAC based catalysis display high stability towards air and moisture, and thus making them attractive alternatives for industrial applications. Throughout the project, synthetic routes towards water soluble CAAC:s have been designed and investigated. Moreover, an approach of evaluating a CAAC-ruthenium catalyst in micellar solutions have been investigated and illustrated promising results regarding activity and stability.

In printed electronics there are many polyelectrolytes to choose from. While polyelectrolytes such as polystyrene sulfonic acid can fulfill many ofthe desired functionalities of a semiconductor, there is a need for other polyelectrolytes with other functionalities, such as functionality at low airhumidity and better cross-linking possibilities, while still functioning as a good semiconductor.Within this thesis, there is a description of general polyelectrolytes, as well as various usages.The synthesis and characterization of new polyelectrolytes that have been developed, based upon diallyldimethyl ammonium chloride (DADMAC)and a derivative of polystyrene sulfonic acid (PSSH) is described.The study and experimental testing of the polymers as polyelectrolytes under different conditions is described.

This work consists of three parts. Part one deals with the syntheses of a number of common Cerambycidae and bark beetle semiochemicals. Additionally, syntheses for three new suspected Cerambycidae semiochemicals were developed. In part two, the elution order and Kovats retention indices of various bark beetle associated semiochemicals were determined on an enantioselective GC-column. In part three, SPME/GC-MS analyses of bark beetle associated fungi cultivations on terpenes were undertaken to find fungal degradation products with known electrophysical activity to bark beetles. A large number of bark beetle semiochemicals were found, including two bark beetle pheromones.

Phosphorescent metal complexes can be incorporated into amyloid-like fibrils, and these fibrils can be decorated with conjugated polyelectrolytes (CPEs). In this study, fac-tris[2-phenylpyridinato-C2,N]irdium(III) complexes [Ir(piq)3] were used as the phosphorescence emitter and Sodium-poly(3-thiophene acetic acid) (PTAA-Na) compounds were used as CPEs. Herein we study the energy transfer processes between the iridium complexes and the CPEs. To investigate these mechanisms, the analysis of the emission quenching and time-resolved measurements were done. Our measurements show that energy can be transfered from singlet state of PTAA to the singlet state of Ir(piq)3. Moreover, incorporation of iridium into amyloid fibrils decreases the importance of energy transfer by the Dexter mechanism. Finally we propose a geometry of interaction to explain the obtained results.

Abnormal aggregation of misfolded proteins is related to numerous neurodegenerative diseases, which include Alzheimer’s, Parkinson’s disease and prion diseases. Luminescent conjugated probes (LCPs) have been used as dyes for these supramolecular assemblies termed amyloid fibrils. To these probes, metalloporphyrin (MP) derivates have been attached to achieve new spectroscopic properties, which will allow for new ways to study protein aggregation diseases.

In this thesis the synthesis of two different LCPs anchored porphyrin derivates are described. The LCPs are synthesized from 3-thiopheneacetic acid and additional thiophene units are added with the use of Suzuki cross coupling reaction. The porphyrin is synthesized from pyrrol, benzaldehyde and methyl-4- formylbenzoate in a condensation reaction. In the first target molecule (TM) the porphyrin and thiophene are coupled with a spacer and the second one is a direct coupling between the two compounds.

γ-Secretase is an enzyme that takes part of the breakdown of amyloid precursor protein (APP) into amyloid-β (Aβ) peptides. Aβ-peptides from this process can be linked to Alzheimer’s disease. γ-Secretase modulators (GSMs) have been reported in the literature to reduce the potentially dangerous variant of Aβ-peptides. However, the mechanism of the binding site for these modulators is poorly understood. In this report substances of affinity based probes (AfBPs) have been prepared that can be used as a method to extract the binding site. The AfBPs were constituted of a cross-linking group, a biotinyl group and a γ-secretase modulator. Different variants of the biotin probe were prepared to investigate if the activity of the original modulator could be retained. The report will show that this could be done.

In the future, the synthesised affinity based probes could be used to understand the mode of action of γ-secretase modulators. For instance the modulator could be incubated with the enzyme and the crosslinking group, when activated, covalently bind to a residue near the binding site. The complex could then be captured on avidin and the binding site be determined.